Spirally-fluted spike



Jan. 15, 1929. 1,698,951

E. c. HOLMES SPIRALLY FLUTED SPIKE Filed May 9, 1925 lNl/E/VTOR WW-w ATTORNEYS Patented Jan. 15, 1929.

UNITED STATES EDWARD C. HOLMES, 0F CINCINNATI, OHIO.

SPIRALLY-FLUTED SPIKE.

Application filed May 9,

My invention relates to improvements in cutting ends for spirally fluted, threaded spikes such as are described in my patent #1,294,268, of February 11, 1919, and which. may be used for inserting into any kind of wood without the necessity of preliminary holes.

It is the object of my invention to improve the construction of such spirally fluted threaded spikes by molding chisel edges on the ends of the spikes and to thus provide spikes which will require much less grinding and which will have sharper cutting edges thereby further limitin the possibility of damage to the threads of the spikes upon inserting them.

Referring to the drawings:

Figure 1 is a side perspective view of an improved spike.

Figure 2 is an enlarged perspective View of the chisel edges with which the end of the spike is provided.

Figure 3 is a bottom plan View of a spike enlarged to the same scale as the end shown in Figure 2.

Figure 4: is a horizontal section through the spike along the lines H in Figure 2.

The spike is provided with a shank portion 1, pointed at one end for insertion into wood. The base of the spike is preferably extended as shown with a rounded bottom portion 2 and a squared top portion 3. Spiral grooves 4 extend from the end of the shank to the rounded base and threads 5 are cut in the shank for securing a tight grip in the wood. The grooves are preferably two in number and they are disposed on opposite sides of the spike. Toward the point of the spike the rooves gradually widen out.

The end of the spike is pointed as has been noted and extended portions 6 extend outwardly from the pointed end and lie at an angle of approximately 45 from a vertical line through the shank longitudinally. These extended portions have flat faces slightly inclined from front to back and may be easily sharpened without the necessity of grinding a round surface as was necessary in sharpening the ends of spikes made according to my invention hereinbefore referred to.

Extending from these flat cutting portions tapering contoured surfaces 7 slope diagonal- 1925. Serial No. 29,212.

ly inwardly and upwardly to positions nearer to the axis of the spike than the chisel edges, so that these contoured surfaces will follow wlthout binding through the parts of the wood into which the chisel edges cut during lnsertion of the spike. The spirally sloping inclined planes 7 are particularly important in connection with a threaded spike because they insure a non-binding bite for the threads of the spike, without the threads being subject to bruising.

As is clearly shown in Figure 2 the spike body adjacent the outer edges of the chisel edges gradually taper outwardly to form the starting threads as indicated at 8 and the two grooves 4 are extended through the spherical portions 7 so that the chisel edges will cut into the wood and the cut wood will force its way up through the grooves from the pointed end toward the head of the spike.

The end structure of spikes made in accordance with my present invention are more satisfactory than my old spikes in that they make a cleaner cut into wood and they further are more thoroughly held in the wood by the threads.

The ease with which spikes made in accordance with my invention will cut into wood, is of great importance as my spikes are adapted to cut into wood and bore their own hole, so that the threads will bind to hold the spike in position. A drill may be used for inserting my spike and as the spike is self-boring and requires no blow with a hammer to start it, the cutting edge and arrangement of the point of the spike is the essential operating part of the spike which enables it to accomplish its double purpose.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent,is:

1. A screw spike comprising a head having a shank of uniform diameter throughout, with screw threads formed thereon, said shank having a cone-shaped end and a pair of spirally arranged flutes of uniform curvature on opposite sides of the shank, the flutes being deeper at the drill point and shallower upward, and said cone-shaped end provided with flat cutting portions projecting above the cone surface and formed on corresponding walls of the two opposite spiral flutes.

2. A screw spike comprising a head havupward, and said cone-shaped end provided ing a shank of uniform diameter throughout, with flat cutting portions projecting above with screw threads formed thereon, said the cone surface and formed on correspond- 10 shank hating a cone-shaped end and a pair of ing walls of the two opposite spiral flutes, and

5 spirally arranged flutes of uniform curvawith the threads on the shank extending from tnre on opposite sides of the shank, the flutes the ends of the flat portions. being deeper at the drill point and shallower EDWVARD G. HOLMES. 

